From rochus@felix.anorg.chemie.tu-muenchen.de Fri Feb 16 04:27:10 1996 Received: from felix.anorg.chemie.tu-muenchen.de for rochus@felix.anorg.chemie.tu-muenchen.de by www.ccl.net (8.6.10/950822.1) id EAA03881; Fri, 16 Feb 1996 04:15:36 -0500 Received: by felix.anorg.chemie.tu-muenchen.de (940816.SGI.8.6.9/930416.SGI) for chemistry@www.ccl.net id KAA01528; Fri, 16 Feb 1996 10:11:06 +0100 From: "Rochus Schmid" Message-Id: <9602161011.ZM1526@felix> Date: Fri, 16 Feb 1996 10:11:05 +0100 X-Mailer: Z-Mail (3.2.0 26oct94 MediaMail) To: chemistry@www.ccl.net Subject: Summary: TS-search/ imag. freq. Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Dear netters, Recently I've posted the following question to the list: On Feb 12, 6:13pm, Rochus Schmid wrote: > Subject: CCL:TS-search / imag. freq. > Dear netters, > > I have a question concerning TS-search and confirmation of it by a vibrational > analysis: > > I've located a TS (DGauss 3.0, LDA-level, DZVP Basis) by EF with the > convergence criterion of the max. component of the (cartesian) gradient vector > to be less than 0.0008 au (which is the default in Dgauss as suggested by > Andzelm for the DZVP-level). > > The mass weigthed Hessian matrix (2nd derivs. calculated analytically) shows > three imag. frequencies. One is large (700 1/cm) and the other two are small > (less than 50 1/cm). These two and four other small, but real frequencies > should represent the six degrees of rotation and translation which are not zero > since I'm not exactly at the stationary point. Correct? > > After projecting out these six degrees of freedom only one neg. frequency > remains (about 700 1/cm). > > Can I trust in that? > Or is it necessery to tighten the convergence criterion? > What is your experience? > > Every comment or advise is highly appreciated. Thanx in advance. > (I will summarize.) > > Greetings from Munich to all of you, > > Rochus > >-- End of excerpt from Rochus Schmid I've got a lot of responses. Many thanks to: Konrad HINSEN, FREDERIC A. VAN-CATLEDGE, Martin Kaupp, Aldert Westra Hoekzema, Amiram Goldblum, Frank Jensen. As a conclusion from all these answers on could say: - the imag. frequencies with low absolute wavenumbers are presumably rotational or translational degree of freedom. - the threshold of 0.0008 is not very tight. I will try to use the TIGHT keyword which means a threshold of 0.0005. - Martin Kaupp suggested to use also a finer integration grid, to get a better description of curvature. - By animating the low imag. frequencies one could check, wether it is rotation or translation. I think, this is a very good idea. Unfortunately, the UNICHEM interface allows only to animate the normal modes of the projected Hessian. This option would be very helpfull in my eyes. In the end, I think I don't have to bother too much about it. Even a tighter convergence criterion will not severely change the situation. But I will check it out. Thanx to all once again. Please excuse me crude English. By the way: DGauss 3.0 offers analytic second derivs. (if you don't use pseudo potentials) and is VERY fast. So there are no artefacts from e.g. single side numeric differentiation. Greetings, Rochus -- ******************************************************************************** Rochus Schmid Technische Universitaet Muenchen Tel. ++49 89 3209 3140 Anorganisch Chemisches Institut 1 Fax. ++49 89 3209 3473 Prof. W. A. Herrmann E-mail: Lichtenbergstrasse 4 rochus@felix.anorg.chemie.tu-muenchen.de 85747 Garching ******************************************************************************** From janetc@cache.com Fri Feb 16 09:42:18 1996 Received: from tribeca.ios.com for janetc@cache.com by www.ccl.net (8.6.10/950822.1) id JAA06630; Fri, 16 Feb 1996 09:39:54 -0500 Received: from [206.20.33.29] (ppp-29.ts-1.hp.idt.net [206.20.33.29]) by tribeca.ios.com (8.6.11/8.6.9) with SMTP id JAA28960 for ; Fri, 16 Feb 1996 09:30:33 -0500 X-Sender: janetc@tribeca.ios.com Message-Id: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Fri, 16 Feb 1996 09:38:06 -0400 To: chemistry@www.ccl.net From: janetc@cache.com (Janet Cicariello-Cook) Subject: Conference Dates - Summary of Responses Hi Everyone, A while ago I asked for the dates of conferences of interest to the comp. chem community. I received a few responsed pointing me to web sites containing lists of upcoming meetings. I was not already familiar with all of these,and also received a few requests for a summary, so I'm posting the URL's here for anyone who's interested. http://hackberry.chem.niu.edu/Conferences.html gopher://www.ccl.net:73/1m/info/conferences http://www.chemie.uni-regensburg.de/%7Ec5008/KONFERENZEN/ I have also recently been told that the Comp Chem Gordon Conference is 6/30-7/5 Janet ********************************************************************* * * * Janet Cicariello-Cook, Ph.D. * * Applications Scientist ############### * * CAChe Scientific - Oxford Molecular ## ##### ##### * * 1200 Route 22 East ## ##### ##### * * Suite 2000 ## ##### ##### * * Bridgewater, NJ 08807 ## #### #### * * ph: (908) 253-3610 ## ### ### * * fax: (908) 725-0296 ## ## ## * * e-mail: janetc@cache.com ############### * * http://www.cache.com/ * * * ********************************************************************* From amasunov@shiva.Hunter.CUNY.EDU Fri Feb 16 21:12:22 1996 Received: from hcrelay.hunter.cuny.edu for amasunov@shiva.Hunter.CUNY.EDU by www.ccl.net (8.6.10/950822.1) id VAA12249; Fri, 16 Feb 1996 21:10:16 -0500 Received: from shiva.hunter.cuny.edu (amasunov@shiva.hunter.cuny.edu [146.95.128.96]) by hcrelay.hunter.cuny.edu (8.6.12/george0995) with SMTP id VAA27747; Fri, 16 Feb 1996 21:14:40 -0500 Date: Fri, 16 Feb 1996 21:11:06 -0500 (EST) From: Artem Masunov To: Computational Chemistry List cc: Artem Masunov Subject: CRYSTAL and AMPAC Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Dear All, Recent summary on CRYSTAL & EMBED rises the question: are there any other programs available for periodical systems (I mean more advanced treatment then just empirical force field)? Unfortunately, Crystal92 does not optimize geometry, and Crystal95 is available only for mysterious EEC Human Capital and Mobility Network members (as Crystal Homepage says). AMPAC 2.2 had an option for 1D-periodicals, but it disappeared in later versions instead of expansion into 2,3D-cases. Does anybody knows something else? Any information will be greatly appreciated. Artem __ _________ / \ / _ _ \ Artem Masunov - amasunov@shiva.hunter.cuny.edu / \\ \\ \\ \ Chemistry Department, Hunter College / /\ \\ \\ \\ \ City University of New York / ____ \\ \\ \\ \ 695 Park Avenue, New York, NY 10021 /__/\__/\__\\__\\__\\__\ Tel: (212) 725-0317, Fax: (212) 772-5332 \__\/ \/__//__//__//__/